I'm uploading a scanned TIFF image and coverting it to PDF by checking the "Convert to PDF" option. It did convert but only a portion of the TIFF image was converted to PDF (please see attached file). How can I resolve this conversion error?

I've noticed that all my scanned documents with property size of more than 8.5" x 11" (Letter Size) when converted to PDF are chopped off. The chopped portions are the upper and lower section of the image. Please see another attached multi-tiff image sample for reference.